The invention relates to a hydraulic control arrangement for an automatic transmission of a motor vehicle with a parking lock activation system.
DE 101 36 425 A1 describes a hydraulic control arrangement with a parking lock activation system for an automatic transmission of a motor vehicle. The lock activation system has a locking slide valve in the form of a switching valve and a locking piston-cylinder unit with a locking piston. By supplying operating fluid via the locking slide valve to a first locking pressure chamber, the locking piston can be displaced in a first activation direction. When the locking piston is displaced in a second activation direction contrary to the first activation direction, operating fluid is removed from the first locking pressure chamber. The operating fluid removed from the first pressure chamber upon displacement of the locking piston in the second activation direction flows via the switching valve to a tank. In order to displace the locking piston in the second activation direction, operating fluid is conducted via the locking slide valve into a second locking pressure chamber, the first pressure chamber being separated from the second pressure chamber by the locking piston.
It is the principal object of the present invention to provide a hydraulic control unit for an automatic transmission, by means of which a parking lockup can be quickly and securely activated.